Originally Posted by JLA
For the most part Jack is right, overbore cartridges are just barrel burners, but with todays ever evolving powders and bullets you can to an extent prolong throat erosion by being selective with your powder. Usually in an overbore cartridge like the .243 they will be loaded with slower than youd think powders anyway, but it is possible, and I have seen it done to use an even slower powder to get a cooler burn, but the trade off is lack of efficiency and velocity loss. The best way to minimize throat eronsion IMO, is to shoot the heaviest bullets that your barrel will stabilize and use the slowest powder listed that gives a complete burn.
I used to take care of my barrels and try to baby them. I found that it makes less than 100 shot difference. The .264 I am about to re-barrel has conservatively estimating 600 shots on the barrel. Probably closer to 800. That is really not that bad for a hunting rifle that has lived its entire life shooting loads way over maximum. 95% or those shots were me playing around at the range. It still does not have to be re-barreled. It is about a 3/4" at 100 shooter, but it used to be 3/8" and is opening up pretty regularly. I could sell it and 99% of the people would not see anything wrong in the bore. They would even be thrilled with how it groups.